ht82j30r Holtek Semiconductor Inc., ht82j30r Datasheet - Page 14

• Manufacturer Part Number: ht82j30r
• Description: Ht82j30r/ht82j30a -- 16 Channel A/d Mcu With Spi Interface
• Manufacturer: Holtek Semiconductor Inc.

For the I/O pin to function as an input, the corresponding
bit of the control register must be written as a 1 . This
will then allow the logic state of the input pin to be di-
rectly read by instructions. When the corresponding bit
of the control register is written as a 0 , the I/O pin will
be setup as an output. If the pin is currently setup as an
output, instructions can still be used to read the output
register. However, it should be noted that the program
will in fact only read the status of the output data latch
and not the actual logic status of the output pin.
Pin-shared Functions
The flexibility of the microcontroller range is greatly en-
hanced by the use of pins that have more than one func-
tion. Limited numbers of pins can force serious design
constraints on designers but by supplying pins with
multi-functions, many of these difficulties can be over-
come. For some pins, the chosen function of the
multi-function I/O pins is set by configuration options
while for others the function is set by application pro-
gram control.
Rev. 1.10
External Interrupt Input_0
The external interrupt pin INT0 is pin-shared with the
I/O pin PA5. For applications not requiring an external
interrupt input, the pin-shared external interrupt pin
can be used as a normal I/O pin, however to do this,
the external interrupt enable bits in the INTC0 register
must be disabled.
External Interrupt Input_1
The external interrupt pin INT1 is pin-shared with the
I/O pin PA6. For applications not requiring an external
interrupt input, the pin-shared external interrupt pin
can be used as a normal I/O pin, however to do this,
the external interrupt enable bits in the INTC1 register
must be disabled.
Input/Output Ports
14
External Timer Clock Input
The external timer pin TMR is pin-shared with the I/O
pin PA4. To configure this pin to operate as timer input,
the corresponding control bits in the timer control reg-
ister must be correctly set. For applications that do not
require an external timer input, this pin can be used as
a normal I/O pin. Note that if used as a normal I/O pin
the timer mode control bits in the timer control register
must select the timer mode, which has an internal
clock source, to prevent the input pin from interfering
with the timer operation.
PFD Output
Each device contains a PFD function whose single
output is pin-shared with PA3. The output function of
this pin is chosen via a configuration option and re-
mains fixed after the device is programmed. Note that
the corresponding bit of the port control register,
PAC.3, must setup the pin as an output to enable the
PFD output. If the PAC port control register has setup
the pin as an input, then the pin will function as a nor-
mal logic input with the usual pull-high option, even if
the PFD configuration option has been selected.
PWM Output
The device contains a PWM output shared with pin
PD0. The PWM output functions are chosen via con-
figuration options and remain fixed after the device is
programmed. Note that the corresponding bit of the
port control register, PDC, must setup the pin as an
output to enable the PWM output. If the PDC port con-
trol register has setup the pin as an input, then the pin
will function as a normal logic input with the usual
pull-high option, even if the PWM configuration option
has been selected.
A/D Inputs
These devices can have up to 16 A/D converter inputs
depending upon which package type is chosen. All of
these analog inputs are pin-shared with I/O pins on
HT82J30R/HT82J30A
March 13, 2008